When I first got my Phantom It would yaw on a dime. I did an IMU calibration the other day and it has not worked right since. In addition to yawing wide I get a lot of travel in GPS mode. It doesnt just float forward or backwards. It will travel forward for a while and then maybe backward and kind of in circles. Really no ryme or reason to it.Compass is calibrated correctly before flight. I did another calibration yesterday and used a level to make sure my surface was legit with no help. I know that the level surface wont help if the IMU itself isnt level. I tried the shim method with no results.